to Maintain Currents between Coaxial Cylinders, 89 



Table V. 



Values of ki deduced from Watson's experiments 



with air at 748 mm. pressure. 



V. 



i. 



K 



7H0* 



51-3 











58-0 



600 



380 



374 



63-5 



1200 



425 



418 



72-5 



2400 



360 



354 



79-8 



3600 



340 



334 



Table VI. 



Values of: k 2 deduced from Watson's experiments 



with air at various pressures p. 



p- 



V. 



i. 



fa. 



K n 











760 





52-8 













58-8 



600 



446 



440 



748 



63-5 



1200 



446 



440 





710 



2400 



422 



415 





760 



3600 



450 



443 





430 













47-0 



600 



745 



542 



552 



50-2 



1200 



790 



575 





55-3 



2400 



785 



570 





602 



36U0 



740 



539 





304 













343 



600 



1580 



740 



356 



364 



1200 



1660 



780 





405 



2400 



1520 



712 





437 



3600 



1490 



700 



In Schaffer's experiments the air -was at atmospheric 

 pressure, nnd the variation of the potential with the current 

 was determined for wires in cylinders of different diameters. 

 The results show that the rate of change of the potential 

 with the current, dV/di, is small with the smaller cylinders, 

 but increases rapidly with the radius of the cylinder. It is 

 difficult to form an accurate estimate of the values of V — V 

 for the smaller cylinders, but with the larger cylinders of 

 radii 3*85 and 5*85 centimetres, the rise of potential with the 

 current may be found to a sufficient degree of accuracy, to 

 calculate the values of k. 



